Search for Neutrino-Induced Neutral-Current Δ Radiative Decay in MicroBooNE and a First Test of the MiniBooNE Low Energy Excess under a Single-Photon Hypothesis

We report results from a search for neutrino-induced neutral current (NC) resonant Δ(1232) baryon production followed by Δ radiative decay, with a ⟨0.8⟩  GeV neutrino beam. Data corresponding to MicroBooNE's first three years of operations (6.80×10^{20} protons on target) are used to select single-photon events with one or zero protons and without charged leptons in the final state (1γ1p and 1γ0p, respectively). The background is constrained via an in situ high-purity measurement of NC π^{0} events, made possible via dedicated 2γ1p and 2γ0p selections. A total of 16 and 153 events are observed for the 1γ1p and 1γ0p selections, respectively, compared to a constrained background prediction of 20.5±3.65(syst) and 145.1±13.8(syst) events. The data lead to a bound on an anomalous enhancement of the normalization of NC Δ radiative decay of less than 2.3 times the predicted nominal rate for this process at the 90% confidence level (C.L.). The measurement disfavors a candidate photon interpretation of the MiniBooNE low-energy excess as a factor of 3.18 times the nominal NC Δ radiative decay rate at the 94.8% C.L., in favor of the nominal prediction, and represents a greater than 50-fold improvement over the world's best limit on single-photon production in NC interactions in the sub-GeV neutrino energy range.

Partial penile amputation using a thoracoabdominal stapler in nine dogs

Objectives

To describe a novel technique for partial anatomic penile amputation using a thoracoabdominal stapler in dogs and to report any associated short‐term peri‐operative complications and clinical outcomes associated with the procedure.

Materials and methods

Medical records from a tertiary referral hospital were reviewed for dogs undergoing penile amputation and scrotal urethrostomy between October 2007 and December 2019. Data collected included patient signalment, clinical signs on presentation, indication for penile amputation, surgical technique, duration of surgery, post‐operative complications, and short‐term outcome.

Results

Nine dogs were included in the study. Indications for surgery were for treatment of chronic paraphimosis and priapism (n = 3), recurrent urethral prolapse (n = 2), balanoposthitis (n = 1), masses arising from the penis, prepuce, and/or urethra (n = 2), and penile trauma (n = 1). All dogs underwent a scrotal urethrostomy followed by a partial penile amputation with a thoracoabdominal stapler. All dogs suffered mild post‐operative haemorrhage from the urethrostomy stoma. On recovery from general anaesthesia, 2/9 dogs were painful and another 2/9 dogs were dysphoric. Two dogs experienced incisional complications with mild swelling around the urethrostomy stoma. One dog experienced an infection of the penile amputation site 21 days after surgery. The short‐term outcomes for this procedure were excellent in 8/9 dogs. These outcomes were based on owner assessment of comfort and monitoring throughout the recovery period, manual palpation of the surgical site at the time re‐evaluation, and surgeon visualization of successful voluntary urination 14–35 days after surgery.

Clinical significance

Use of a thoracoabdominal stapler is effective in achieving partial anatomic penile amputation in dogs.

A tetranuclear nickel(II) complex, [Ni4(L)4](ClO4)4·C2H3N·2H2O, with an asymmetric Ni4O4 open-cubane-like core

A tetra­nuclear complex with an open-cubane like structure was synthesized from 2-meth­oxy-6-(pyridin-2-yl-hydrazonometh­yl)-phenol and characterized using micro-analytical and spectroscopic techniques, and single-crystal X-ray diffraction analysis.

A tetra­nuclear complex with an open-cubane-like core structure was synthesized from 2-meth­oxy-6-(pyridin-2-yl-hydrazonometh­yl)phenol (HL), namely, cyclo-tetra­kis­(μ-2-meth­oxy-6-{[2-(pyridin-2-yl)hydrazin-1-yl­idene]meth­yl}pheno­lato)tetra­nickel(II) tetra­kis­(perchlorate) aceto­nitrile monosolvate dihydrate, [Ni₄(C₁₃H₁₂N₃O₂)₄](ClO₄)₄·C₂H₃N·2H₂O, and characterized using micro-analytical and spectroscopic techniques. The crystal-structure determination reveals the formation of a distorted Ni₄O₄ cubane-like core architecture encapsulated by four hydrazone Schiff base (HL) mol­ecules. A open-cube tetra­nuclear architecture is created in which nickel(II) ions of the NiN₂O₃ unit are connected by μ₂-O anions of the phenolate moiety of HL. In this complex, each Ni centre has a slightly distorted square-pyramidal coordination environment. The supra­molecular architectures are stabilized via the presence of various inter­molecular hydrogen bonds and (ar­yl–aryl, ar­yl–chelate and chelate–chelate) stacking inter­actions.

In vitro functional analysis of gRNA sites regulating assembly of hepatitis B virus

The roles of RNA sequence/structure motifs, Packaging Signals (PSs), for regulating assembly of an HBV genome transcript have been investigated in an efficient in vitro assay containing only core protein (Cp) and RNA. Variants of three conserved PSs, within the genome of a strain not used previously, preventing correct presentation of a Cp-recognition loop motif are differentially deleterious for assembly of nucleocapsid-like particles (NCPs). Cryo-electron microscopy reconstruction of the T = 4 NCPs formed with the wild-type gRNA transcript, reveal that the interior of the Cp shell is in contact with lower resolution density, potentially encompassing the arginine-rich protein domains and gRNA. Symmetry relaxation followed by asymmetric reconstruction reveal that such contacts are made at every symmetry axis. We infer from their regulation of assembly that some of these contacts would involve gRNA PSs, and confirmed this by X-ray RNA footprinting. Mutation of the ε stem-loop in the gRNA, where polymerase binds in vivo, produces a poor RNA assembly substrate with Cp alone, largely due to alterations in its conformation. The results show that RNA PSs regulate assembly of HBV genomic transcripts in vitro, and therefore may play similar roles in vivo, in concert with other molecular factors.